I find Downtown Disney during the day is the best time to go if you want a quick bite. When we stayed offsite the night before our reservations, we chose to go by DTD when the stores opened. (9 am). I personally don't find that many locals frequent DTD because of the large tourist population. A Lunch table should be fairly easy to obtain if you go around the general lunch time. Places such as Wolfgang Puck Express, Bongos, House of Blues, Planet Hollywood open up around 11 am for lunch. The Marketplace restaurants open at 9 am.